Aim. Using a specialized fatigue rating scale, to identify risk factors for fatigue syndrome formation in patients hospitalized for COVID-19-induced lung damage at different follow-up periods — at long-COVID and post-COVID. Design. A retrospective observational study. Materials and methods. The study included 100 patients — 60 women and 40 men aged 25 to 84 years, Me — 58 (50–64) years, who underwent hospitalization for lung lesions caused by PCR-confirmed COVID-19 infection. Fatigue was detected in 66% of them. Patients were divided into long-COVID (up to 12 weeks) and post-COVID (more than 12 weeks) groups according to the time period after hospital discharge. Fatigue was assessed using the validated Fatigue Assessment Scale (FAS). With a score of 21 or more, fatigue was considered clinically significant. Key inflammatory markers (ferritin, C-reactive protein, neutrophil-lymphocyte ratio, erythrocyte sedimentation rate) and various medical interventions (vaccination, transfer to the intensive care unit, use of etiotropic and anticoagulant therapy at the outpatient stage) were considered as possible predictors of fatigue, the data on which were taken from medical records. Results. Key inflammatory markers associated with the severity of acute COVID-19 have different prognostic value in the assessment of fatigue. A statistically significant association was found between fatigue syndrome as assessed by FAS and neutrophil-lymphocyte ratio at hospital admission (p = 0.042), erythrocyte sedimentation rate at discharge (p = 0.013), ferritin level at discharge (p = 0.021), whereas a similar association between FAS score and CRP level was not found either at hospital admission (p = 0.775) or at hospital discharge (p = 0.272). Various medical interventions were also associated with the formation of fatigue syndrome. Patients who underwent hospitalization in the intensive care unit were significantly more likely to report fatigue syndrome (p = 0.044, for the long-COVID period p = 0.006), the protective effect of vaccination was significant (p = 0.002, for post-COVID p = 0.009). No association was found between fatigue syndrome and outpatient use of etiotropic therapy (p = 0.459) or anticoagulants (p = 0.358). Conclusion. Fatigue syndrome after a COVID-19 with lung lesions is associated with the features of the therapy administered and the levels of some laboratory markers during the acute phase of infection. Keywords: COVID-19 coronavirus infection, long-COVID, post-COVID, fatigue, Fatigue Assessment Scale, inflammatory markers.
